98 MISSOURI BOTANICAL GARDEN BULLETIN 
which germinate in the earth and send out long thread-like 
shoots which soon come in contact with near-by plants. These 
shoots twine about the stems of such plants and here and 
there form small suckers which tap the food and water sup- 
ply of the host. All connection with the earth is then lost 
and the dodder settles down to its parasitic existence. _The 
plant = becomes a pest, although when once established 
in a bed of flowers or in shrubbery it becomes very difficult 
to eradicate. 
Another epiphytic plant, perhaps better known for its 
various Christmas uses than for the peculiarity of its epi- 
phytic habit, is the mistletoe. In the west and southwest it 
grows so abundantly on the sycamore, fir, pine, and oak, 
as to cause the early death of many trees. Unlike the dodder, 
this plant never has any direct connection with the ground, 
but spends all its life as a parasite. When the waxy berries ~ 
ripen they are eaten by birds, or being extremely sticky, 
may cling to the feet of birds and are thus dispersed from 
tree to tree. Coming to lodge in a crack or a knot-hole these 
seeds germinate and send root-like processes into the host 
tissue. So firmly connected do these become that the union 
appears similar to a natural graft. 
The Garden is very fortunate in the possession of many 
representatives of the tropical and sub-tropical epiphytes. 
One of the latter, ve familiar to many readers, is the 
: —— moss (Tillandsia usneoides L.), sometimes called 
Florida or Louisiana moss from its prevalence in those two 
regions. The plant is especially interesting in that it illus- 
trates the extreme modification in structure and function 
of various organs which may result from an abnormal habit 
of growth. Only weak and insignificant root development 
ever takes place, and this only in the very earliest stages of 
seed germination. Such roots are quickly lost, and the 
mature moss, as one finds it draped gracefully over the 
branches of trees, consists wholly of stems and leaves. The 
plant is not a parasite and does not have any connection with 
the tree upon which it grows. Naturally one might expect 
to find here the question of food and water su ply a serious © 
one. Organic foods, as sugars, are formed ty the green 
pigment of the leaves, as is true in normal plants. The 
entire outer surface of the stems and leaves are covered with 
extremely small scales which during a rain greedily absorb 
the falling drops much as a sponge absorbs water. This 
water is held by capillary attraction and is given up to the 
plant as seeded ery drop of such water is precious and 
must be made to go as far as possible. It is not rising 
then that one finds that during a dry spell the Seales be- 
